Refrigeration equipment for ice rinks (including outdoor and indoor hockey, skating and curling rinks) typically comprises a refrigeration compressor, a brine chiller, a brine-to-ice heat exchanger usually embedded in a substrate below the ice, brine lines and a brine pump for circulating the refrigerated brine through the heat exchanger. The operation of ice slab refrigeration equipment requires a significant amount of power. For example, refrigerator compressors of about a one hundred horsepower capacity (i.e. 77 tons), operating about 50% of the time on the average throughout the year, are required to maintain good ice quality in the case of a single ice rink located in a typical community centre. The average cost for operating refrigeration equipment for a typical ice rink is now in the thousands of dollars monthly, and this cost is expected to increase with ever escalating energy costs. Accordingly, there is an increasing need to improve the energy efficiency of ice rink equipment.
The brine pump of a conventional ice rink refrigeration system operates continuously at a constant speed (usually about 1800 RPM). Heretofore, no attempt had been made to vary the speed of the brine pump, perhaps because of concerns over reduced ice quality or perhaps because it was felt that little energy savings could be achieved by modifying the brine pump because the cost of running the brine pump is rather less than the cost of running the refrigerator compressor.